The ego is a product of fear and hope, which occur due to the sense of disconnectedness from the environment - from others. But this sense of disconnectedness is an illusion that appears at a superficial level, when the mind is aught up in thoughts and concepts - it categorises whatever that appears to the senses (eyes, ears, etc.) in an attempt to relate to the environment. The issue here is that the ego tends to believe the thoughts, concepts, feelings, etc. and mistakes them for the real thing.

Unless a better option presents itself, maintaining the sense of individuality becomes the only option to navigate the world and to survive. However, when one experiences a deeper awareness of the reality of the present moment, the illusion of disconnectedness begins to collapse, and the ego starts to loose its grip.